Power supplies with battery backup and basic fault reporting means for security and life safety systems have been in existence for decades. These power supply systems provide some mechanism for basic fault detection and reporting as required by industry specifications. Most commonly, visual indicators and relay contacts are the primary means for fault notification. In these traditional power supply systems, power system control or parameter change necessitates direct physical change of the device by an on-site technician and cannot be done otherwise. Examples of existing power supply systems with this kind of fault notification are illustrated in FIG. 1 and FIG. 2.
FIG. 1 provides a simplified block diagram of an existing power supply system 100. In FIG. 1, a complete power supply/charger board 101 includes an isolated AC-DC power converter 102 which is a power supply that converts AC power into isolated 12V or 24V DC power outputs. The DC output from the isolated AC-DC converter 102 is sent to one or more output terminals under the control of control and fault detection circuitry 103. For example, DC is provided to three pairs of output terminals DC1, DC2 and DC3 as shown. DC1 is a normal constant-on output while the DC2 and DC3 outputs are controlled by a Fire Alarm Interface (FAI) signal (not shown). The DC2 output is on when the FAI signal is inactive and DC3 is on when the FAI signal is active. The control and fault detection circuitry 103 also detects faults in the system including loss of AC power (AC Fault), and system faults. The system faults include “output voltage out of range” and “battery not present.” The control and fault detection circuitry 103 also handles the battery power transfer in event of an AC power outage. Charger 104 charges the battery 107 and maintains it at near full capacity when AC power is normal. The system fault relay 105 and AC fault relay 106 are normally energized, that is, energized when there is no fault condition present. When AC power is lost, the AC fault relay 106 is de-energized, causing a change in the contact state and either closing or opening its various provided output contacts. The output contacts can be used to signal some upper level control device to react to the fault condition. Similarly, when any one of the system faults occurs, the system fault relay 105 will change its contact states and thereby notify an upper control device of the fault condition. The LED indicators 108 are a group of LED indicators that are utilized to indicate the presence of AC input, DC output, specific fault conditions and FAI signal status. For example, one green LED may indicate AC power present, a second green LED may indicate DC1 output normal, a third green LED may indicate that either DC2 or DC3 has power, a red LED may indicate FAI activation, a yellow LED may indicate an AC Fault, a second yellow LED may indicate a system fault and a third yellow LED may indicate a reverse battery condition.
FIG. 2 provides a simplified block diagram of another existing power supply system 200. The functionality of the power supply system 200 is similar to the power supply system 100, except that the power supply system 200 does not have an FAI interface and does not provide the two FAI controlled DC outputs (DC2 and DC3). In FIG. 2, the FAI signal is input to a Notification Appliance Circuit (NAC) power control board 209. The power to the NAC power control board 209 is provided by the DC input DC1 from the main power supply board 201 as shown.
A drawback of the traditional existing power systems described above and exemplified in FIG. 1 and FIG. 2, is that service personnel must be on site to troubleshoot every fault condition, and to perform periodic maintenance. For example, nowadays a security company may manage thousands of security cameras spread out in many different buildings. Sometimes those cameras can get stuck and require the power to be cycled (i.e. reset the camera). The security company has to send technicians to the field to reset every camera that gets stuck.
Another problem with traditional existing power systems involves battery maintenance. To ensure the battery is functioning properly, a service technician must go to every job site to test the battery operation at a certain period of time.
Another drawback of these traditional existing power systems is that they do not provide system operating parameters and therefore it is difficult to detect potential failures before the failure happens.
This issue also presents itself within the area of power distribution and output control in existing power supply systems for security and life safety applications because these systems cannot be remotely monitored and controlled. If a device connected to the distribution and control output is about to fail, there is no way to tell in existing systems. This creates problems for some highly sensitive applications such as, for example, security equipment in banks, or other similar institutions requiring high security among other examples.
One specific problem is that when a security device connected to the power distribution system output seizes up or otherwise gets stuck, a power cycle is required to reset the device. In this case, the power supply system will have to cycle power for all the security devices connected to the common power supply which requires temporarily taking all security devices using that power supply “off-line.” Among other concerns, removing power to all devices in this manner causes problems because some sensitive equipment cannot tolerate power interruption. A specific problem for security systems is that access controls are temporarily disabled causing a security risk during the reset.